JP2018178723A - Internal combustion engine control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine control system for improving the ignitability of fuel in the case that a temperature in a combustion chamber is high, in a self-ignition combustion type internal combustion engine.SOLUTION: An internal combustion engine control system 801 controls an operation of an internal combustion engine 10 by a diffusion combustion mode for self-igniting fuel in air. A water introduction part 33 and an ultrasonic wave generation device 35 function as an "additive substance supply device" which can supply a hydrogen peroxide (H) for generating an OH-radical as an additive substance for generating a radical in an intake passage 21 or a combustion chamber 12. A supply control part 71 controls a hydrogen peroxide supply amount. Since the hydrogen peroxide is dissolved at a temperature not lower than 700K, and can create the OH-radical, the ignitability of the fuel can be improved even in the case that a temperature in the combustion chamber at fuel injection in the vicinity of a top dead port is high in a degree of 800 to 900K.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an internal combustion engine control system that controls the combustion of an internal combustion engine.

  Heretofore, there has been known a technique for improving the self-ignitability of fuel with respect to combustion control of an internal combustion engine. For example, the compression self-ignition engine disclosed in Patent Document 1 includes means for supplying ozone into the combustion chamber, and O radicals generated by decomposition of ozone promote self-ignition of fuel in homogeneous charge compression ignition (HCCI) combustion. Let Further, according to the load of the engine, the fuel injection timing is delayed to adjust the ozone supply timing when the load is high.

Patent No. 5906982

As described in Patent Document 1, ozone is decomposed at a temperature in the combustion chamber of about 500 to 600 K to generate O radicals. Hereinafter, [K] of the temperature unit is Kelvin.
Radicals are unstable active substances, and most of them disappear in a short time after being generated. For example, the time constant of the O radical is several tens of μs, and it is considered to decrease to several thousand to several tens of thousands or less in less than 1 ms after generation.

  Further, the temperature near the compression end (i.e., the top dead center of the piston) in the high compression ratio engine is about 800 to 900 K which is higher than the decomposition temperature of ozone. Therefore, when injecting a fuel near the compression end of a high compression ratio engine, it is difficult to supply O radicals to the fuel by the supply of ozone. Therefore, in the prior art of Patent Document 1, there is a problem that the ignitability of the fuel can not be improved when the temperature in the combustion chamber is high.

  The present invention has been made in view of such a point, and its object is to provide an internal combustion engine control system for improving the ignitability of fuel when the temperature in the combustion chamber is high in a self-igniting combustion type internal combustion engine. It is to provide.

The internal combustion engine control system of the present invention is an internal combustion engine control system that controls the operation of the internal combustion engine (10) by a combustion mode in which fuel in air is self-ignited and comprises one or more additive supply devices (33, 35, 40) and a supply control unit (71).
The additive supply device can supply an additive that generates radicals in the intake passage (21) or the combustion chamber (12). The supply control unit controls the supply amount of the additive substance.
And, the additive substance contains at least a substance capable of generating a radical at a temperature of 700 K or more.

Here, "capable of generating radicals at a temperature of 700 K or more" is interpreted in the sense that it is capable of generating a practically effective amount of radicals in view of technical common knowledge in this technical field.
That is, in general, decomposition of a chemical substance is understood as a phenomenon of first-order lag response in which chemical equilibrium moves from the start of reaction to decomposition and converges after infinite time. In other words, the decomposition is not 100% complete after a finite time from the start of the reaction, and a very small amount of substance strictly remains undegraded.
For example, ozone disclosed in Patent Document 1 almost decomposes at 700 K and most of the generated O radicals are thought to disappear immediately, but still, only a trace amount of O radicals in the time of combustion cycle order of the internal combustion engine Should be present.

However, such a small amount of O radical is not considered to be practically effective in improving the ignitability in light of common technical knowledge. Therefore, even if the amount of production is not strictly 0, the generation of O radicals at that level is excluded from the interpretation of “the ability to generate radicals”.
In short, the specific matter “the radical can be generated at a temperature of 700 K or more” is intended to exclude the prior art of Patent Document 1 in which only ozone is supplied into the combustion chamber.

  Also, "capable of generating radicals at a temperature of 700 K or more" does not mean that radicals can be generated at any high temperature range of 700 K or more, for example, several thousand K. If the formation of radicals by the additive substance can be realized, for example, in a temperature range of 800 to 900 K, it is interpreted that this requirement is satisfied. Of course, in light of the technical common knowledge of internal combustion engines, it is self-evident that it is not necessary to assume a temperature range that exceeds the temperature in a realistic combustion chamber.

  In the present invention, the additive capable of generating radicals in the intake passage or the combustion chamber is supplied at a temperature of 700 K or more. As a result, for example, in the case of the diffusion combustion system of gasoline, even when the temperature in the combustion chamber at the time of fuel injection near the top dead center is 800 to 900 K, effective amounts of radicals can be generated to improve the ignitability.

Specifically, the internal combustion engine control system is a hydrogen peroxide supply device (33, 35) capable of supplying hydrogen peroxide which generates OH radicals in the intake passage or combustion chamber at a temperature of 700 K or more as an additive substance supply device. It is preferable to have. Alternatively, both hydrogen peroxide and ozone may be supplied.
In addition, as a hydrogen peroxide supply device, for example, a technology disclosed in Japanese Patent No. 4103525, in which water is irradiated with ultrasonic waves to be changed to hydrogen peroxide can be used.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram of the internal combustion engine control system by 1st Embodiment. The figure which shows the installation state of a combustion chamber temperature sensor. The supply control flowchart by 1st, 2nd embodiment. The map which determines the amount of hydrogen peroxide supplied according to (a) combustion chamber temperature and (b) operation load. The figure which compares the decomposition characteristic of ozone and hydrogen peroxide. The characteristic view which shows the relationship between a crank angle and a combustion chamber temperature. The block diagram of the internal combustion engine control system by 2nd Embodiment. The block diagram of the internal combustion engine control system by 3rd Embodiment. The supply control flowchart by 3rd Embodiment. Map to determine the hydrogen peroxide supply according to the amount of exhaust unburned HC and soot. The block diagram of the internal combustion engine control system by 4th Embodiment. The supply control flowchart by 4th Embodiment. The map which determines the hydrogen peroxide or ozone supply amount according to (a) combustion chamber temperature, (b) driving load, (c) discharge unburned HC, and SOOT amount. The map which determines ratio of (a) hydrogen peroxide and ozone supply amount, (b) (hydrogen peroxide supply amount / ozone supply amount) according to the temperature in a combustion chamber. The flowchart of (a) supply control of each mode by 5th Embodiment, (b) supply control of a mode shift period. The figure which shows the change of the fuel-injection time by combustion mode.

Hereinafter, a plurality of embodiments of an internal combustion engine control system will be described based on the drawings. The following first to fourth embodiments are collectively referred to as "the present embodiment". Substantially the same configurations in the plurality of embodiments will be assigned the same reference numerals and descriptions thereof will be omitted.
The internal combustion engine control system of the present embodiment is a control system that controls the operation of the internal combustion engine by a combustion method in which fuel in the air is self-ignited and burned. The present embodiment assumes that the present invention is basically applied to a gasoline engine that uses gasoline as fuel. In addition, about the possibility of application to fuels other than gasoline, it describes in other embodiment.

In a gasoline engine, it is effective to improve theoretical efficiency by increasing the compression ratio. This theory is based on the fact that the thermal efficiency η approaches 1 as the compression ratio ε is increased in the following equation representing the relationship between the thermal efficiency η, the compression ratio ε, and the specific heat ratio γ.

However, when the compression ratio is high, knocking, that is, self-ignition of the end gas tends to occur, and therefore, it is an issue to suppress the knocking. As a solution, there is a "diffuse combustion method" which is a combustion method similar to a diesel engine, in which the compressed air is injected with fuel while being self-ignited while being injected with fuel.
In this diffusion combustion method, since there is no mixture in the end gas, knock freeing is possible. However, gasoline has low ignitability, so self-ignition is difficult, and a technique for improving the ignitability is required.

In order to solve the above problems, Patent Document 1 (Japanese Patent No. 5906982) proposes a technology for improving the ignition performance of gasoline by adding ozone. In this technology, the combustion reaction can be promoted by O radicals generated by ozonolysis according to Chemical Formula 1.

However, ozone decomposes at about 500 to 600 K to generate O radicals. The generated radicals are unstable active substances, and most of them disappear rapidly with a time constant on the order of several tens of μs.
On the other hand, when the fuel is injected near the compression end (that is, the top dead center of the piston) in the diffusion combustion system, the temperature of the compression end in the high compression ratio engine is about 800 to 900 K. Therefore, in the technology of ozone addition according to the prior art of Patent Document 1, it is difficult to supply radicals to the fuel.

Therefore, in the first to third embodiments, in the diffusion combustion method of a high compression ratio gasoline engine, radicals are effectively injected when fuel injection is performed near the top dead center where the temperature in the combustion chamber becomes a high temperature of about 800 to 900K. We propose the technology to supply fuel.
Specifically, by supplying "the additive capable of generating radicals at a temperature of 700 K or more", the generated radicals are prevented from being eliminated immediately even in an environment of 800 to 900 K. As an example of the additive substance, an embodiment in which hydrogen peroxide generating OH radical is supplied will be described in detail.

In the fourth embodiment, an embodiment in which a mode in which hydrogen peroxide is supplied as an additive that generates radicals and a mode in which ozone is supplied is switched will be described.
Hereinafter, the descriptions of the additive substances will in principle be described as “hydrogen peroxide” and “ozone” in the specification and in the drawings as “H ₂ O ₂ ” and “O ₃ ” using chemical formulas.

First Embodiment
The first embodiment will be described with reference to FIGS. 1 to 6.
The internal combustion engine 10 is, for example, a multi-cylinder engine mounted on a vehicle, and a piston 13 reciprocates in a cylinder 15 of each cylinder. In FIG. 1, the head side partial cross section of one cylinder is illustrated. The illustration of the diversion from the intake passage 21 to the intake manifold 11 and the joining of the exhaust manifold 14 to the exhaust passage 22 is omitted.

  The combustion chamber 12 is a space defined by the inner surface of the cylinder 15, the lower surface of the cylinder head 16, and the crown surface 130 of the piston 13. The intake valve 17 opens and closes an intake port communicating with the combustion chamber 12 from the intake manifold 11. The exhaust valve 18 opens and closes an exhaust port communicating with the exhaust manifold 14 from the combustion chamber 12. The fuel injection valve 30 injects fuel into the combustion chamber 12.

In FIG. 1, the air filter and the throttle valve in the intake passage 21 and the exhaust gas purification catalyst and the like in the exhaust passage 22 are not shown.
In the internal combustion engine control system 801 according to the first embodiment, a water tank 31, a water supply passage 32, and a water introduction unit 33 for introducing water (i.e., H ₂ O) of the water tank 31 into the intake passage 21 are provided. . In addition, an ultrasonic wave generation device 35 is provided in the intake passage 21 downstream of the inlet 34 of the water supply passage 32.

The ultrasonic wave generator 35 applies ultrasonic waves to the water introduced into the intake passage 21 by the water introducing unit 33 to generate hydrogen peroxide. That is, the water introducing unit 33 and the ultrasonic wave generator 35 in the first embodiment function as a "hydrogen peroxide supply device".
Japanese Patent No. 4103525 discloses a technology of an exhaust gas purification apparatus in which the exhaust gas is irradiated with ultrasonic waves around 200 kHz in the upstream of a three-way catalyst or the like, and water contained in the exhaust gas is changed to hydrogen peroxide. ing. In this technology, hydrogen peroxide is used to improve purification performance by oxidizing unburned substances of HC and CO, and to eliminate HC poisoning to the NOx storage reduction catalyst.
In the first embodiment, on the other hand, hydrogen peroxide is generated during inhalation for another purpose.

In the first embodiment, hydrogen peroxide is an example of “an additive that generates radicals in the intake passage 21 or the combustion chamber 12”. Further, the “hydrogen peroxide supply device” configured by the water introducing unit 33 and the ultrasonic wave generation device 35 corresponds to one form of the “added material supply device”.
Hydrogen peroxide is decomposed by the chemical formula 2 in the intake passage 21 or the combustion chamber 12 to generate OH radicals. The supply of OH radicals into the combustion chamber 12 improves the ignitability of the fuel.

  In FIG. 1, in the vicinity of the internal combustion engine 10 of the intake passage 21, a temperature sensor 61 such as a thermocouple for detecting the intake temperature is provided. Further, a temperature sensor 62 such as a thermocouple is provided which protrudes from the inner surface of the cylinder 15 into the combustion chamber 12 and directly detects the temperature in the combustion chamber. However, at least one of the temperature sensors 61 and 62 may be provided.

  Further, as a configuration in which the temperature sensor is provided in the combustion chamber 12, as shown in FIG. 2, a temperature sensor 63 may be provided on the lower surface of the cylinder head 16 adjacent to the fuel injection valve 30. However, when the spray injected from the fuel injection valve 30 is applied to the temperature sensor 63, the temperature in the combustion chamber can not be accurately detected. Therefore, the protrusion amount d3 of the temperature sensor 63 into the combustion chamber 12 is preferably zero or as small as possible in order to avoid interference with the spray. On the other hand, since the temperature sensor 62 provided at a position distant from the fuel injection valve 30 is less affected by the spray, there is no problem even if the protrusion amount d2 is relatively large.

The engine ECU 70 includes a supply control unit 71, an injection control unit 72, and the like, and controls the operation of the internal combustion engine 10.
The supply control unit 71 controls the “supply amount of the additive substance that generates a radical” in a generalized expression. Specifically, in the first embodiment, the supply control unit 71 controls the supply amount of hydrogen peroxide by the water introduction unit 33 and the ultrasonic wave generation device 35.
The injection control unit 72 controls the fuel injection amount and the injection timing of the fuel injection valve 30.

The supply control unit 71 estimates the temperature in the combustion chamber based on the intake air temperature detected by the temperature sensor 61 provided in the intake passage 21 or burns the temperature detected by the temperature sensor 62 provided in the combustion chamber 12 Acquired as indoor temperature.
Further, the supply control unit 71 obtains the operating load of the internal combustion engine 10. For example, in the case of the internal combustion engine 10 of a vehicle, the accelerator opening degree is acquired from the accelerator ECU 75 as a parameter representing a driving load.

FIG. 3 shows a flowchart of hydrogen peroxide supply control according to the first embodiment. In the following description of the flowchart, the symbol S represents "step". In the flowcharts of the later embodiments, the same steps as those in the first embodiment are denoted by the same step numbers, and the description thereof is omitted.
The supply control unit 71 acquires the temperature in the combustion chamber from the temperature sensor 61 or 62 in S1 and acquires the operation load from the accelerator ECU 75 in S2. The execution order of S1 and S2 does not matter.

In S4A, the supply control unit 71 determines the hydrogen peroxide supply amount according to the temperature and the operating load of the combustion chamber. Since it is difficult for the fuel to self-ignite as the temperature in the combustion chamber is lower and the operation load is lower, it is preferable to increase the hydrogen peroxide and improve the ignitability under such conditions that the self-ignition is difficult.
Therefore, as shown in FIG. 4A, the supply control unit 71 increases the hydrogen peroxide supply amount as the temperature in the combustion chamber is lower. Further, as shown in FIG. 4B, the supply control unit 71 increases the hydrogen peroxide supply amount as the operation load decreases.
In S5A, the supply control unit 71 operates the water introducing unit 33 as the “hydrogen peroxide supply device” and the ultrasonic wave generation device 35 based on the determined supply amount.

Next, with reference to FIG. 5 and FIG. 6, the operation and effect according to the first embodiment will be described.
FIG. 5 shows the relationship between the temperature and the decomposition rate of hydrogen peroxide and ozone.
Ozone has a high decomposition rate even in the low temperature L region, and as the temperature rises, the decomposition rate rises toward the high temperature H region with a relatively gentle slope. On the other hand, hydrogen peroxide has a remarkably low decomposition rate to ozone in the low temperature L region. Then, as the temperature rises, the decomposition rate rises with a relatively rapid inclination toward the high temperature H region.
For example, the L region corresponds to a temperature region of about 500 to 600 K, and the H region corresponds to a temperature region of about 800 to 900 K.

FIG. 6 shows the relationship between the crank angle correlated with the position of the piston 13 and the temperature in the combustion chamber.
From the intake stroke to the middle of the compression stroke, the temperature in the combustion chamber is lower than the decomposition temperature Tres_O _{3 of} ozone. From the end of the compression stroke, the temperature in the combustion chamber starts to rise rapidly, and the temperature when fuel is injected at the top dead center is equal to the decomposition temperature Tres_H ₂ O _{2 of} hydrogen peroxide. In the combustion stroke after the top dead center, the temperature in the combustion chamber further rises and reaches a peak, and then gradually falls.
Here, for example, based on 700 K, the temperature Tres_O _{3 at} which ozone is decomposed to generate O radicals is lower than 700 K, and the decomposition temperature Tres_H ₂ O ₂ of hydrogen peroxide is higher than 700 K. In short, hydrogen peroxide decomposes at high temperature compared to ozone, and can generate OH radical at a temperature of 700 K or more.

As described above, in the first embodiment, by supplying hydrogen peroxide to the intake air, OH radicals can be generated in the combustion chamber 12, and the ignitability of the fuel in the diffusion combustion can be improved.
Further, the supply control unit 71 can improve the ignitability by increasing the amount of hydrogen peroxide supplied as the fuel is less likely to be ignited as in the case where the temperature in the combustion chamber is low or the operating load is low.
Further, by irradiating the water introduced into the intake passage 21 with the ultrasonic wave by the ultrasonic wave generator 35, hydrogen peroxide can be easily generated.

Second Embodiment
The second embodiment will be described with reference to FIG.
In the internal combustion engine control system 802 of the second embodiment having an exhaust gas recirculation (so-called EGR) system, an EGR passage 23 branched from the exhaust passage 22 and communicated with the intake passage 21 is provided. When the EGR valve 24 is open, a part of the exhaust gas containing moisture generated by the combustion is recirculated to the intake passage 21 via the EGR passage 23.

An ultrasonic wave generator 35 is provided in the EGR passage 23. The ultrasonic wave generator 35 functions as a “hydrogen peroxide supply device” by irradiating ultrasonic waves to the exhaust gas to be recirculated and changing the water content in the exhaust gas into hydrogen peroxide.
The hydrogen peroxide supplied from the ultrasonic wave generator 35 is supplied to the combustion chamber 12 together with the intake air to generate OH radicals, thereby improving the ignitability of the fuel in the diffusion combustion.

The flowchart of the hydrogen peroxide supply control according to the second embodiment and the map of the hydrogen peroxide supply amount according to the combustion chamber temperature and the operation load can be applied to FIGS. 3 and 4 of the first embodiment. In S5A of the flowchart, the supply control unit 71 operates the ultrasonic wave generator 35 as the “hydrogen peroxide supply device” to supply hydrogen peroxide into the exhaust gas recirculated to the intake passage 21.
The second embodiment has the same effects as the first embodiment. Further, in the internal combustion engine control system 80 having the exhaust gas recirculation system, the water content in the exhaust gas can be effectively used to supply hydrogen peroxide.

Third Embodiment
The third embodiment will be described with reference to FIGS.
As shown in FIG. 8, in addition to the configuration of the control system 801 of the first embodiment, the internal combustion engine control system 803 of the third embodiment measures the amount of exhaust unburned HC and SOOT (so-called “soot”) in exhaust gas. A measuring device 50 for notifying the feed control unit 71 is provided in the exhaust passage 22.
In the internal combustion engine 10 of a vehicle, for example, the amount of unburned HC and the amount of soot tend to increase during acceleration or cold of the vehicle, for example.

S1 and S2 of the supply control flowchart of FIG. 9 are the same as those of FIG. 3 of the first and second embodiments. At S3 after S2, the supply control unit 71 acquires the amount of exhaust unburned HC and the amount of soot.
As shown in the map of FIG. 10, the supply control unit 71 reduces the amount of unburned substance discharged by increasing the amount of hydrogen peroxide supplied as the amount of discharged unburned HC and SOOT in the exhaust gas increases.

That is, the supply control unit 71 determines the hydrogen peroxide supply amount in accordance with three parameters of the combustion chamber temperature, the operation load, the discharged unburned HC, and the SOOT amount in S4A of the flowchart. Then, the supply control unit 71 operates the ultrasonic wave generation device 35 as a “hydrogen peroxide supply device” based on the determined supply amount in S5A.
The third embodiment has the same effects as the first embodiment. In addition, by increasing the hydrogen peroxide supply amount as the amount of discharged unburned HC and SOOT increases, the oxidizing power can be increased and the amount of unburned substance discharged can be reduced.

Fourth Embodiment
The fourth embodiment will be described with reference to FIGS. 11 to 16.
As shown in FIG. 11, in the internal combustion engine control system 804 of the fourth embodiment, an EGR passage 23 of the exhaust gas recirculation system is provided as in the control system 802 of the second embodiment.
In addition, the internal combustion engine control system 804 includes an ozone supply device 40 capable of supplying ozone as an additive substance that generates O radicals in the intake passage 21 or the combustion chamber 12.

A part of the intake air flows into the ozone supply device 40 via the inflow passage 41 branched from the upstream side of the intake passage 21. The intake air containing ozone supplied by the ozone supply device 40 is introduced to the downstream side of the intake passage 21 via the first outflow passage 43 when the first valve 44 is opened, and the second valve 46 is opened. , And introduced into the EGR passage 23 via the second outflow passage 45.
The ozone supplied to the intake passage 21 via the first outflow passage 43 generates O radicals in the intake passage 21 or the combustion chamber 12.

すなわち、オゾン供給装置４０は、ＥＧＲ通路２３にオゾンを供給し、排気中の水分を利用して過酸化水素を生成する作用を通じて、「過酸化水素供給装置」としての機能を兼ねる。ＥＧＲ通路２３で生成された過酸化水素は、吸気通路２１又は燃焼室１２内にＯＨラジカルを発生させる。 The ozone supplied to the EGR passage 23 via the second outflow passage 45 converts the water in the recirculated exhaust into hydrogen peroxide according to the chemical formula 3.

That is, the ozone supply device 40 also functions as a “hydrogen peroxide supply device” through the action of supplying ozone to the EGR passage 23 and generating the hydrogen peroxide using the moisture in the exhaust gas. The hydrogen peroxide generated in the EGR passage 23 generates OH radicals in the intake passage 21 or the combustion chamber 12.

  By the way, in the configuration in which all the ozone supplied by the ozone supply device 40 is supplied to the intake passage 21 while the second valve 46 is always closed, there is substantially no difference from the prior art of Patent Document 1. On the other hand, in the configuration in which all the ozone supplied by the ozone supply device 40 is supplied to the EGR passage 23 while the first valve 44 is always closed, there is a possibility that some ozone not used for the generation of hydrogen peroxide may remain. Also, it is considered that there is substantially no difference from the first to third embodiments.

Therefore, in the fourth embodiment, both the first valve 44 and the second valve 46 are simultaneously opened to supply both hydrogen peroxide and ozone in at least a partial area of the combustion chamber temperature and the operating load. The point has technical significance.
The supply control unit 71 adjusts the opening degree of each of the valves 44 and 46 in the area where both hydrogen peroxide and ozone are supplied, thereby providing absolute amounts of hydrogen peroxide supply amount and ozone supply amount, and peroxidation with respect to ozone supply amount. Control the ratio of hydrogen supply.

  As described above, ozone decomposes at about 500 to 600 K, and most of the generated O radicals disappear immediately. Therefore, particularly at a temperature of 700 K or more, hydrogen peroxide which is more difficult to decompose than ozone is mainly supplied Is more advantageous for improving the ignitability. However, even if the temperature is 700 K or more, the O radicals in the combustion chamber 12 do not completely disappear, and the effect of ozone supply can be expected to some extent. Therefore, it is an object of the fourth embodiment to comprehensively control the supply amounts of ozone and hydrogen peroxide.

Note that, as a configuration for supplying hydrogen peroxide, instead of “a configuration for supplying ozone to the EGR passage 23 and changing the water content in the exhaust gas to hydrogen peroxide” shown in FIG. Similarly, the ultrasonic wave generator 35 may be used. In that case, the ozone supply device and the hydrogen peroxide supply device are configured independently.
Further, in the control system 804 of FIG. 11, as in the third embodiment, the exhaust unburned HC and soot amount measuring device 50 are provided in the exhaust passage 22, but this may not be provided.

  S <b> 1, S <b> 2 and S <b> 3 of the supply control flowchart of FIG. 12 are the same as those of FIG. 9 of the third embodiment. In S4B, ozone is added to S4A in FIG. 3 and FIG. 9, and the supply control unit 71 determines the supply amount of hydrogen peroxide and ozone. Similarly, in S5B, ozone is added to S5A in FIGS. 3 and 9, and the supply control unit 71 operates the hydrogen peroxide and ozone supply device.

13 (a), (b), and (c) respectively indicate the “hydrogen peroxide supply amount” in the vertical axis in FIGS. 4 (a), (b) and FIG. 10 as the “hydrogen peroxide or ozone supply amount”. It is a map replaced by.
The supply control unit 71 increases the supply amount of at least one of hydrogen peroxide or ozone as the temperature in the combustion chamber is lower or the operation load of the internal combustion engine 10 is lower. In addition, the supply control unit 71 increases the supply amount of at least one of hydrogen peroxide and ozone as the amount of discharged unburned HC and SOOT in the exhaust gas increases. For example, the supply control unit 71 increases the supply amount of one of hydrogen peroxide and ozone according to the above relationship, and the other supply amount is constant regardless of the temperature in the combustion chamber, the operation load, the amount of discharged unburned HC, and the amount of SOOT. Good.

Further, the supply control unit 71 changes the balance between the hydrogen peroxide supply amount and the ozone supply amount according to the temperature in the combustion chamber. That is, the supply control unit 71 increases the ratio of the amount of supplied hydrogen peroxide to the amount of supplied ozone as the temperature in the combustion chamber increases, and decreases the ratio of the amount of supplied hydrogen peroxide to the ozone supply as the temperature in the combustion chamber decreases. Let
That is, based on, for example, about 700 K, ozone decomposed at low temperature is preferentially supplied when the temperature in the combustion chamber is relatively low, and hydrogen peroxide decomposed at high temperature is preferentially supplied when the temperature in the combustion chamber is relatively high. Supplied. Thereby, the ignitability of the fuel can be effectively improved according to the temperature in the combustion chamber.

As one example, as indicated by a solid line in FIG. 14A, the supply control unit 71 makes the increase gradient of the ozone supply amount relative to the decrease amount of the temperature in the combustion chamber larger than the increase gradient of the hydrogen peroxide supply amount. As the temperature in the combustion chamber is lower, both the hydrogen peroxide supply amount and the ozone supply amount are increased.
As a result, as indicated by the solid line in FIG. 14B, the ratio of (the amount of supplied hydrogen peroxide / the amount of supplied ozone) increases as the temperature in the combustion chamber increases.

As another example, as indicated by a broken line in FIG. 14A, the supply control unit 71 sets the ozone supply amount to 0 when the temperature in the combustion chamber is above the critical temperature Tc, and the temperature in the combustion chamber is below the critical temperature Tc. In the region, the lower the temperature in the combustion chamber, the higher the ozone supply.
In this case, as indicated by a broken line in FIG. 14B, the ratio of (the amount of supplied hydrogen peroxide / the amount of supplied ozone) becomes infinite in the region above the critical temperature Tc. Thus, the concept of "increasing the feed ratio" includes an increase to infinity.

Next, combustion mode switching control to which the fourth embodiment is applied will be described with reference to FIG. 15 and FIG. The internal combustion engine control system 804 is configured as a system capable of switching between the diffusion combustion mode and the premixed self-ignition combustion mode.
The premixed auto-ignition combustion mode is a mode in which a premixed mixture of fuel and air is compressed for auto-ignition combustion, and corresponds to HCCI combustion or the like described in Patent Document 1. In addition, another fuel injection valve may be provided in the intake passage for the premixed self-ignition combustion mode.
The diffusion combustion mode is a mode in which combustion is performed by injecting fuel into compressed air, as described above, as in the diesel engine.

  The premixed auto-ignition combustion mode is good in ignitability but not suitable when the operation load is high. The diffusion combustion mode can be applied even at high loads, but is characterized by having poor ignitability. Therefore, engine ECU 70 switches the combustion mode in accordance with the operation load and the like so as to selectively use the advantages of both modes. For example, the injection control unit 72 of the engine ECU 70 changes the injection timing of the fuel injection valve 30.

As shown in FIG. 15, in the premixed self-ignition combustion mode, fuel is injected at the beginning of the intake stroke or compression stroke, that is, before the middle of the compression stroke where ozone is mainly decomposed, in order to mix fuel and air. Ru. Therefore, in this mode, the supply control unit 71 can supply O radicals to the fuel by preferentially supplying ozone, and the ignitability can be improved.
On the other hand, in the diffusion combustion mode, fuel is injected near the top dead center at the end of the compression stroke. Therefore, in this mode, the supply control unit 71 can supply OH radicals to the fuel by preferentially supplying hydrogen peroxide that decomposes at a higher temperature than ozone, and can improve the ignitability.

FIG. 16 (a) shows a flowchart of supply control in each combustion mode.
In S11, the combustion mode is determined. In the diffusion combustion mode, YES is determined in S11, and the process proceeds to S12. In the case of the premixed self-ignition combustion mode, it is determined as NO in S11, and the process proceeds to S13.

In the diffusion combustion mode, the supply control unit 71 supplies only hydrogen peroxide or increases the ratio of (hydrogen peroxide supply amount / ozone supply amount) in S12. Supplying only hydrogen peroxide is equivalent to increasing the ratio of (hydrogen peroxide supply amount / ozone supply amount) to infinity.
In the premixed auto-ignition combustion mode, the supply control unit 71 supplies only ozone or decreases the ratio of (hydrogen peroxide supply amount / ozone supply amount) in S13. Supplying only ozone is equivalent to setting the ratio of (hydrogen peroxide supply amount / ozone supply amount) to zero.
As a result, in the premixed self-ignition combustion mode, the ignitability can be improved by O radicals mainly generated by ozone, and in the diffusion combustion mode mainly by OH radicals generated by hydrogen peroxide.

FIG. 16B shows a flowchart of supply control in the mode transition period.
Here, it is assumed that only hydrogen peroxide is supplied in the diffusion combustion mode and only ozone is supplied in the premixed self-ignition combustion mode. For example, a predetermined time or a period in which a predetermined crank angle range is moved is defined as a “mode transition period” from when the engine ECU 70 determines the change of the combustion mode according to the fluctuation of the operation load or the like.

In S21, it is determined whether it is in the mode transition period.
If it is determined YES in S21 during the mode transition period, the supply control unit 71 supplies both hydrogen peroxide and ozone in S22. When the mode transition period is over, either hydrogen peroxide or ozone is supplied depending on the combustion mode after transition. Thereby, the ignition stability at the time of combustion mode switching can be secured.

As described above, the fourth embodiment is effectively applied to a system capable of switching between the diffusion combustion mode and the premixed self-ignition combustion mode. Although supplying ozone in the premixed self-ignition combustion mode itself is a technique disclosed in Patent Document 1, Patent Document 1 does not mention switching to the diffusion combustion mode. Furthermore, Patent Document 1 does not suggest the idea of generating OH radicals by supplying hydrogen peroxide in the diffusion combustion mode at all.
Therefore, the fourth embodiment has a technical significance that is unique to appropriately using the additive substance to generate a radical along with the switching of the combustion mode.

(Other embodiments)
The radical generated by the additive substance (a) may be a radical other than the O radical and the OH radical exemplified in the above embodiment. In other words, the additive substance supplied by the additive substance supply device may be a substance capable of generating any radical at a temperature of 700 K or more, in addition to ozone or hydrogen peroxide. Moreover, as long as the harmful effect in a chemical reaction does not arise, multiple types of radicals may be mixed and supplied.
(B) The fuel of the internal combustion engine may be alcohol fuel or gas fuel other than gasoline.
(C) The application of the internal combustion engine is not limited to vehicles, and may be for other vehicles and general machines.

  As mentioned above, the present invention is not limited to the above-mentioned embodiment at all, and can be implemented in various forms in the range which does not deviate from the meaning of an invention.

10 ... Internal combustion engine,
12 ... combustion chamber,
21 ... Intake passage,
35: Ultrasonic generator (hydrogen peroxide supply device, additive material supply device),
40 ... ozone supply device (hydrogen peroxide supply device, additive substance supply device),
71 ··· Supply control unit,
801-804 ... internal combustion engine control system.

Claims (15)

An internal combustion engine control system for controlling the operation of an internal combustion engine (10) by a combustion method in which fuel in air is self-ignited and burned,
One or more additive substance supply devices (33, 35, 40) capable of supplying additive substances that generate radicals in the intake passage (21) or the combustion chamber (12);
A supply control unit (71) for controlling the supply amount of the additive substance;
Equipped with
The internal combustion engine control system, wherein the additive substance includes at least a substance capable of generating a radical at a temperature of 700 K or more.   The internal combustion engine according to claim 1, further comprising a hydrogen peroxide supply device (33, 35) capable of supplying hydrogen peroxide which generates OH radicals in the intake passage or the combustion chamber at a temperature of 700 K or more as the additive substance supply device. Control system.   The internal combustion engine control system according to claim 2, wherein the supply control unit increases the hydrogen peroxide supply amount as the temperature in the combustion chamber is lower or the operating load of the internal combustion engine is lower.   The hydrogen peroxide supply device can generate hydrogen peroxide by irradiating ultrasonic waves to the water introduced into the intake passage by the water introduction portion (33) for introducing water into the intake passage and the water introduction portion The internal combustion engine control system according to claim 2 or 3, including an ultrasonic wave irradiation device (35). An EGR passage (23) is provided to recirculate part of the exhaust into the intake passage,
The internal combustion apparatus according to claim 2 or 3, wherein the hydrogen peroxide supply device includes an ultrasonic wave irradiation device (35) capable of generating hydrogen peroxide by irradiating the water in the exhaust gas flowing back through the EGR passage with ultrasonic waves. Engine control system.   The internal combustion engine control system according to any one of claims 2 to 5, wherein the supply control unit increases the hydrogen peroxide supply amount as the amount of exhaust unburned HC or SOOT in the exhaust gas increases. The additive substance supply apparatus further includes an ozone supply apparatus (40) capable of supplying ozone that generates O radicals in the intake passage or the combustion chamber,
The internal combustion engine according to any one of claims 2 to 6, wherein the supply control unit supplies both hydrogen peroxide and ozone in a region of the combustion chamber temperature or at least a part of the operating load of the internal combustion engine. Control system. An EGR passage (23) is provided to recirculate part of the exhaust into the intake passage,
The internal combustion engine control system according to claim 7, wherein the ozone supply device also has a function as a hydrogen peroxide supply device capable of generating hydrogen peroxide by irradiating the water in the exhaust gas recirculating the EGR passage with ultrasonic waves. .   The internal combustion engine control system according to claim 7 or 8, wherein the supply control unit increases the supply amount of at least one of hydrogen peroxide or ozone as the temperature in the combustion chamber is lower or the operating load of the internal combustion engine is lower. .   The internal combustion engine control according to any one of claims 7 to 9, wherein the supply control unit increases the supply amount of at least one of hydrogen peroxide or ozone as the amount of exhaust unburned HC or SOOT in the exhaust gas increases. system.   The internal combustion engine control system according to any one of claims 7 to 10, wherein the supply control unit increases the ratio of the hydrogen peroxide supply amount to the ozone supply amount as the temperature in the combustion chamber is higher. In an internal combustion engine control system capable of switching between a diffusion combustion mode in which fuel is injected and burned into compressed air and a premixed self-ignition combustion mode in which pre-mixture of fuel and air is compressed and self-ignition combustion
The supply control unit is
In the diffusion combustion mode, only hydrogen peroxide is supplied, or the ratio of hydrogen peroxide supply to ozone supply is increased;
The internal combustion engine control system according to any one of claims 7 to 11, wherein in the premixed self-ignition combustion mode, only ozone is supplied or the ratio of hydrogen peroxide supply amount to ozone supply amount is decreased.   The internal combustion engine control system according to claim 12, wherein the supply control unit supplies both ozone and hydrogen peroxide in a mode transition period in which the diffusion combustion mode and the premixed self-ignition combustion mode are switched.   The internal combustion engine control system according to any one of claims 1 to 13, wherein the supply control unit acquires a temperature detected by a temperature sensor (62, 63) provided in the combustion chamber as the temperature in the combustion chamber.   The internal combustion engine control system according to any one of claims 1 to 13, wherein the supply control unit estimates the temperature in the combustion chamber based on the intake air temperature detected by a temperature sensor (61) provided in the intake passage.

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